Nobody knows. For several years many doctors have recommended that pregnant women and breastfeeding mothers avoid certain foods such as dairy products, peanuts and other nuts, seafood, etc. However, the general opinion in allergy and immunology is that exposure to small amounts of potential allergens (substances that cause allergy) actually helps prevent allergies. And breast milk passes on only very small amounts of potential allergens to the baby that, together with antibodies and other immune factors, will help baby develop a tolerance to these allergens. There is no guarantee, of course, but the best thing is to breastfeed exclusively and do not worry.